1. Field of the Invention
The present invention relates to a display device for use in a typewriter or the like having an oblong display unit capable of displaying a part of one line to be typewritten.
2. Description of the Prior Art
Such an electronic typewriter with a conventional display device generally has a display capacity of several tens of characters at maximum despite the fact that it can type more than one hundred characters in a line. Thus, in case a sentence stored in an auxiliary memory inside or outside the typewriter need be displayed for confirmation before actual typing, the operator can see only a part of said sentence and has to conduct a character-by-character shifting of the display for confirming the entire sentence.
As an example, FIG. 1 shows a conventional typewriter of this type, provided with a memory MEM that may be for example a semiconductor memory, a key K1 in the keyboard for KB for reading a sentence stored in said memory MEM and eventually in an external memory, an oblong display unit DSP for displaying a part of said sentence thus read, and a shift key K2 for shifting the sentence displayed on said display unit DSP. The above-explained typewriter functions in the following manner when, as an example, the memory MEM stores a sentence as shown in FIG. 2, composed of 34 characters including spaces and punctuation marks. In case of a display capacity of 16 digits, the sentence read from the memory MEM under the instruction by the key K1 is displayed on the display unit DSP as shown in FIG. 3. Then, in response to each actuation of the shift key K2, the displayed content is shifted to the left by one character, in the order as shown in FIGS. 4A to 4D. Consequently the shift key K2 has to be repeatedly actuated for seeing the entire sentence in case it is long. In order to prevent such inconvenience the above-mentioned shift key K2 can be replaced by a line-shift key similar to the page-shift key known in CRT display devices. In such case, in response to the actuation of the line-shift key, the characters displayed as shown in FIG. 3 are entirely changed to as shown in FIG. 5A, and then as shown in FIG. 5B in response to the repeated actuation of said line-shift key. Although such structure reduces the cumbersomeness of key operations, the display on the display unit DSP often causes the words to be split as shown in FIGS. 5A and 5B, affecting the legibility of the displayed sentence and rendering erros in spelling less easily discoverable.